Detonating device



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Nov. 17, 1964 F. PORTER DETONATING DEVICE 3 Sheets-Sheet 2 Filed Jan. 27, 1961 Nov. 17, 1964 F. PORTER DETONATING DEVICE 3 Sheets-Sheet 3 Filed Jan. 27, 1961 1475 (0/7 ff For fer INVENTOR.

ATTO/P/VEV 3,l?,ll9 Patented Nov. 17, 1964 3,157,119 DETQNATHNG DEVMIE Layton F. Porter, 4022 dilverweod, Houston 25, Tux. Filed Jan. 27, 1961, et. No. 35,363 4 Claims. (til. rise-21a) This invention relates to a device for detonating an explosive charge in a tubular structure and is particularly concerned with a device for detonating a string shot in stuck drill pipe or tubing within an oil well.

During the drilling of wells, particularly oil wells, the drill pipe or tubing will sometimes become stuck with the result that further operations must cease until the stuck condition is remedied. While one or" the major causes of stuck pipe or tubing is collapse or cave-in of the well bore, there are other causes.

However, without regard to cause, when a string of pipe, or tubing becomes stuck, it is usually desirable to remove the unstuck or tree portion of the string before attempting to deal with the stuck portion.

conventionally, this is accomplished by first determining what is known in the art as the free-point, i.e. the depth of the first unstuck coupling above the stuck point. This is normally accomplished with a device known as a free point indicator, which is lowered into the well while suspended on a cable capable of conducting electricity. This device will normally be comprised of two members adapted to be attached to the wall of the drill pipe, means associated therewith to measure the amount of relative movement between the two members when the drill pipe is stretched or torqued, and a surface indicator electrically connected thereto by means of the cable. Thus assembled the device is lowered into the well and a series of measurements taken until the lowest point of normal free movement is determined, which point is called the free point.

After the free point is located, and hence its depth determined, a string shot is lowered into the well, again on an electrical conductor, and positioned adjacent the free point. Then, torque is applied to the string in the direction which would unscrew the pipe and the string shot is detonated; detonation of the shot causing the free point coupling'to unscrew or back-oil under the continuing torque on the string.

While, it is sometimes convenient to speed up this operation by running the free point indicator and the back-off string shot together, the operation is still somewhat slow and possesses other disadvantages. For example, the electrical cable required to run these tools is expensive and requires heavy and expensive hoisting machinery. Moreover, the cable is subject to being shorted by well fluid leaking through flaws in the insulation and the sensings reported at the well surface, are difiicult to interpret properly.

It is, therefore, an object of this invention to provide an integrated, self-contained, free-point-selective, shotdetonating, back-off tool requiring no sensory communication with the well surface.

It is another object of this invention to provide a shotdetonating back-off tool which may be lowered into the well by means of a simple, relatively inexpensive Wire line of the piano-wire type employing relatively inexpensive hoisting equipment.

Another object of this invention is to provide chargedetonating means of the type described which is torqueresponsive with respect to detonation.

Other objects and advantages are provided by the invention, some of which will appear from the following detailed description of those two embodiments thereof which are illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a side elevation of a mechanical embodimerit of the invention showing the device suspended in drill pipe in armed condition.

FIGURE 2 is an -enlarged elevation view of the device shown in FIGURE 1 with the outer portion broken away along the lines 22 to expose the arming and firing mechanism of the device.

FIGURE 3 is a side elevation of an electrical embodiment of the invention showing the device suspended in drill pipe, again in armed condition. 7

FIGURE 4 is an enlarged elevation view of the device shown in FIGURE 3 with the outer portion broken away along the lines 4-4 to expose the electrical arming and firing assembly.

FIGURE 5 is an enlarged elevation view of the device shown in FIG. 2 with the outer portion broken away and taken at an angle 90 degrees counter-clockwise to lines 2-2, to expose the arming and firing mechanism of the device.

FIGURE 6 is an enlarged section taken along line 6-6 of FIGURE 2 and further illustrates the arming and firing mechanism shown in FIGURE 2.

In the following detailed description of the two embodiments illustrated in the accompanying drawings, reference numerals have been employed as follows:

5 drill pipe 38 trigger 6 well bore 39 spring 7 coupling 46 flange 8 coupling 41 guide 9 rod 42 cam 1t bowspring 43 cam follower 11 rings 44 0 rings 12 set screws recesses 13 stop 46 0 ring 14 cylindrical housing 47 recess 15 lower section .8 recess 16 upper section 49 insulators 17 sleeve string shot conductor 18 spring 51 contact 1% collars 52 contact 2d fingers 53 (not used) 21 arming pin 54 mounting 22 adapter conductor 23 string shot 56 contact 24 wire line 57 contact 26 rings 58 (not used) 27 set screws 59 conductor 28 cap guide 29 firing pin 61 sear extension 30 guides 62 slots T l spring 63 battery 32 operating handle d4 (not used) 33 O ring arming mechanism 34 recess 66 firing mechanism 35 recess 67 passageway 36 flange 7t sear rod 37 sear In the illustrated mechanical embodiment of this invention (shown in FIGURES 1, 2, 5 and 6) a rod 9 is suspended from the end of a wire line 24 which extends into drill pipe 5 in well bore 6 from suitable hoisting equipment located at the well surface but not shown and not forming a part of this invention. At the lower end of rod 9 there is a bowspring 10, conveniently secured by means of rings 11 and set screws 12; rings 11 being moveable along rod 9 when set screws 12 are loosened, for reasons explained hereinafter.

Above bowspring 10, a substantial portion of rod 9 is encased by a cylindrical housing 14 which is conveniently sealed at its engagement with rod 9 by means of 0 rings 44 carried in recesses 45. Housing 14 is rotatable around and shiftable axially along rod 9. However, the extent '5 while the device is suspended therein. However, lower section 15 of housing 14, comprises a section of enlarged diameter which serves to house and support an arming assembly, generally indicated at 65; and a firing assembly, generally indicated at 66.

Arming assembly 65 has an arming pin 21, carried at one end by means of expansion spring 39, which spring is carried in turn by guide 41 of sear 37. The other end of pin 21 passes through the Wall of housing 14 and is conveniently sealed by means of O ring 46 carried in recess 47. To maintain spring 39 under compression, the

shank of pin 21 is provided with a spring retaining flange 40 which, in addition to keeping spring 39 compressed against sear 37, serves to limit the outward movement of pin 21 through the wall of housing 14. A sleeve member 17 carried slidably around the outer wall of housing 14 where it is confined between collars 19 normally overrides the outer extension of the wall-engaging end of pin 21, causing pin 21 to abuttingly engage extension 61 of sear 37, thereby obviating firing of the device by preventing withdrawal of rod 70 of sear 37, fixed at one end to sear extension 61, from firing pin recess 35; To insure against the inadvertent downward movement of sleeve 17. and attendant premature arming of the device an expansion spring 18 is positioned between lower collar 19 and sleeve 17 thereby maintaining sleeve 17 in normally abutting relation with upper collar 19; thus, preventing the outward arming movement of pin 21.

Sleeve 17 is then outfitted with a plurality of expendable fingers 20 adapted to. be frictionally received and retained in circumferentially disposed slots 62. Thus, after they device is lowered into the drill pipe and it becomes tie.- sirable to arm it, the entire device is simply drawn upwardly through the drill pipe until fingers 20 engage a coupling, as for example, coupling 8 of FIGURE 2, whereupon continued withdrawal of the device will drive member is capable of yielding to the force of engagement created by rotation of the rod 9 with respect to the sleeve 17 downwardly against the force of spring 18 until I pin 21 can pass outwardly over the upper end of sleeve 17 under the force of spring 39. When pin 21 is thus driven outwardly, to the extent permitted by "flange 40, it

will no longer abut sear extension 61 so that sear rod 70 may then be withdrawn from recess 35 of pin 29 by simply applying sufficient pressure thereto to overcome the now relatively slight sear-retaining-force created by partially expanded spring 39.

Firing assembly 66 is generally comprised of a firing pin 29, sear 37 and a trigger 38. To provide convenient carriage for pin 29, a pair of guides 30 are secured to the inner wall of housing 14, as by welding, and extend inwardly'the'refrom to slidably engage the shank of pin 29.. The lower end of pin 29 extends slidably through the end wall of housing 14, which is conveniently sealed by means of O ring 33 carried in recess 34, toprovide operating handle 32, while the upper end of pin 29 terminates in passageway 67 of adapted 22. To drive pin '29, it is outfitted with an expansion spring 31, which is confined between the end wall of housing 14 and flange 36, the later being conveniently formed on the lower shank portion of pin 29. Then, at the mid-section of pin 29-there is a receiving recess 35 adapted to engage the end of sear rod 70 when pin 29 is withdrawn downwardly into cocked position by means of operating handle 32.

Convenient carriage of scar 37 is achieved by means of guide 60 which is conveniently secured to the inner wall of housing 14, as-by welding, and extends inwardly of sear 37 will be brought into close proximity (with respect to its vertical alignment) to trigger 38 which depends from the roof of recess 42 of rod 9.

Thus, if after the device is armed and cocked, there is counter-clockwise rotation of housing 14 (and hence rotation of extension 61) with respect to rod 9 (and hence trigger 33) while rod 9 is shifted fully upwardly with respect to housing 14, trigger 38 will pass over sear extension 61. However, if this rotation occurs while rod 9 is shifted fully downwardly with respect to housing 14, then trigger 38 Will engage sear extension 61, and if the device is armed, continued rotation will cause sear rod 76) to be withdrawn from recess 35 of pin 29, thereby releasing pin 29 to be driven into cap 28 under the force of spring 31 to detonate string shot'23. However, as indicated above, even if rotation occurs while rod 9 is shifted fully downwardly, unless the-device is armed, sear 37 cannot be withdrawn upon being engaged by trigger 38 because of the abutting engagement between arming pin 21 and sear extension 61. In such an instance therefore, trigger 33, which is of yieldabiy rigid construction, will be temporarily deformed since no other housing 14.

Referring now to FIGURES 3 and 4 of the drawings;

In the electrical embodiment, battery 63 is secured to wire line 24 ni any convenient manner, as for example by the use of conventional fastener means. Battery 63 is then connected to an arming contact 56, which is carried by flange 4i and in turn by pin 21, by means of conductor 59 which enters housing 14 through one of insulators 49. Contact 56 then terminates in alignment with, and in normally spaced relation to contact 57 which is carried by housing 14. Firing contact 52, carried by mounting 54 and in turn by housing 14, is connected to contact 57 by means of conductor 55, contact 52 being thus disposed in normally spaced relation to another firing contact 51 which depends from the roof of recess 48 in rod 9. Contact 51 is then connected to cap 28, which is conveniently taped to wire line 24, by means of conductor 50, which passes out of housing 14 through the other .of insulators 49. From cap. 23 the circuit is then closed by means of conductor 68 which connects'cap 2S and battery 63.

When the device is lowered into a well and armed by the downward movement of sleeve 17, in the manner above described, pin 21 will move outwardly under the force of spring 39 (which in this embodiment, abuts rod 9, which carries guide 41 rather than sear 37, recess 48 having been repositioned to better accommodate the electrical circuitry) until stop 58 thereof engages, the wall of housing 14 thereby closing contacts 56 and 57 to put the device in armed condition. Here againit will be noted that, once the device is armed, counterclockwise rotation of housing 14 with respect to rod 9 will cause contact 52 to engage contact 51 (assuming of course,

housing 14) thereby closing the entire circuit and electrically detonating cap 28 and in turn string shot 23 carried by wire line 24. Again however, if rod 9 should be shifted fully upwardly with respect to housing 14, such rotation will not effect closure of the firing circuit because contact 51 will pass over contact 52.

It is, of course, known that when torque is applied to a stuck drill pipe the pipe will twist. Thus, at the surface of the well the pipe appears to rotate when torque is applied and, the extent to which this surface rotation occurs is dependent upon both the physical character of the pipe and the depth of the stuck point. It, therefore, follows that upon the application of torque to the pipe the uppermost of any two points along the length of the pipe and above the stuck point will rotate to a greater degree than will the lowermost point. Since the upper bowspring, carried by the housing, secures the housing against rotation relative to the pipe at the point of contact between pipe and bowspring and the lower bowspring secures the rod member against relative rotation at its point of contact, the application of torque to the pipe after the device is lowered therein, will always produce rotation of the housing with respect to therod member unless one or both of the bowsprings is within or below the stuck point in which event rotation of the housing relative to the rod will be de minimis or nonexistent.

To avoid premature firing, it is important that the spacing of the triggering elements be pre-set before each back-ofi attempt. In both the electrical and mechanical embodiments this is accomplished by means of cam 42 and cam follower 43. When it is desired to make a backoit attempt rod 9 is drawn upwardly until cam follower 43 is positively engaged by cam 42 thereby aligning the triggering elements with respect to their vertical disposition, then rod 9 is lowered until stop 13 abuts housing 14 whereupon the triggering elements are brought into horizontal alignment and the device is ready for a backoif attempt.

Back-oif operations are conveniently conducted with either of the illustrated embodiments by lowering the device into the drill pipe to a point within or below the stuck point. Rod 9 is then drawn upwardly by means of wire line 24 to engage fingers in a coupling, as for example stuck coupling 8 of FIGURES 1 and 3, thereby depressing sleeve 17 to actuate the arming assembly. Further, this same upward movement of rod 9 will engage cam 42 and cam follower 43 to vertically align the trigger elements of the firing assembly.

Arming, and vertical alignment of the trigger elements .having been achieved, rod 9 is again lowered into housing 14, which is independently secured to the drill pipe by bowspring 25, to bring the trigger elements into horizontal alignment. The first back-cit attempt may then be made. This is done by applying torque to the pipe in the direction that would unscrew it. As torque is applied and the pipe is twisted, housing 14 rotates relative to rod 9 and drives the trigger element carried by housing 14 toward the trigger element carried by rod 9. If at this point one or both of bowsprings l0 and 25 are positioned within a stuck joint, as shown in FIG- URES 1 and 3, the relative movement between housing 14 and rod 9 will not be sufiicient to bring their respective trigger elements into engagement and the device will not fire. When this occurs, it will therefore signify that the device is positioned either below or within the stuck point and must be raised.

Assuming that the first back-01f attempt was made within or below the stuck point, the device is raised some reasonable distance, such as 100 feet, the trigger elements are again aligned vertically and horizontally, and torque is again applied to the pipe. If at this point, the device is now positioned above the stuck point, the relative rotation between housing 14 and rod 9 will be increased sufficiently to cause engagement of the trigger elements carried by those members, and the device will fire.

Because of the relatively long length of the device, particularly the rod member, string shot 23 which is always carried above the upper bowspring, either by rod 9 or wire line 24, will be disposed opposite at least one unstuck coupling, as indicated by the positioning of string 23 opposite coupling 7 while the bowsprings straddle coupling 8. This being the case, when the shot is detonated, the shock of detonation coupled with the force of the continuing torque upon the pipe, will break the coupling opposite the shot, which coupling may then be unscrewed to permit removal of that portion of the drill string above the unscrewed coupling.

It has been found that the spacing between the trigger elements when the device is in aligned condition should be about of an inch for most applications. Efifective adjustment of this spacing may, of course, be had by increasing or decreasing the distance between the bowsprings thereby translating more or less of the twist on the pipe into corresponding rotation between the housing and rod members. Moreover, if it is desired to employ the device with varying diameters of pipe, the diameter of the bowspring may be reduced or increased to accommodate the diameter of the pipe with which the device is to be employed.

While the foregoing specification gives a detailed description of the two illustrated embodiments of this invention, this description has been given only to facilitate an understanding of the invention by those skilled in the art. The invention itself will admit of other embodiments of equally good construction and operational capacity. Accordingly, the scope of the invention is not to be limited to the details of the illustrated embodiments.

What I claim is:

1. In a device for detonating an explosive charge in a tubular structure, the combination of;

an elongated member having one end adapted for connection to a line for suspending said member in a tubular structure; means at the other end of said elongated member for securing said member against movement relative to said tubular structure when suspended therein; support means carried by said elongated member;

said support means being movable on said elongated member; means coupled tosaid support means for securing said support means against movement relative to said tubular structure when suspended therein; an explosive charge carried by said elongated member adjacent said support means; firing means arranged to detonate said explosive charge,

said firing means including a firing assembly carried by said elongated member and responsive to a pre-determined relative displacement between said support means and said elongated member, caused by twisting the tubular structure, to initiate detonation of said explosive charge. 2. A device, as described in claim 1, wherein, said firing assembly comprises a release means having a first member attached to said elongated rod and a second member attached to said support means,

said first and second members being spaced apart before the tubular structure is twisted and coming into engagement after the tubular structure is twisted to initiate detonation of said explosive charge. 3. A device, as described in claim 1, wherein, said firing assembly comprises an electrical circuit having a first contact attached for movement with said elongated member and a second contact attached for movement with said support means,

said first and second contacts being spaced apart I before the tubular structure is twisted and closing after the tubular structure is twisted to initiate detonation of said explosive charge.

4. In a device for detonating an explosive charge in a tubular structure having multi-sections coupled together, the combination of;

an elongated member having one end adapted to be connected to a suspension line;

a housing member carried by and at least partially surrounding said elongated member,

said housing being movable on said elongated member; 4

means at the other end of said elongated member securing said elongated member against movement 7 relative to said tubular structure when disposed therein; means for securing said housing against movement relative to the tubular structure; an explosive charge carried by said elongated member; means carried by said elongated rod for firing said explosive charge,

said firing means being responsive to the relative movement between said housing and said elongated member When'the tubular structure is twisted to initiate firing at a pre-set displacement; means for arming said firingmeans,

said arming means including a sensing member carried on the outside of said housing and operable to engage a coupling joint of the tubular structure; said firing means being capable of firing said charge only after said sensing member has engaged a cou' pling joint.

References Cited in the file of this patent UNITED STATES PATENTS 'Kinle'y Dec. MacDonald et al. a Oct. Connolly Dec. Sweetman May 15, Alexander "June 17, Alexander July 8, Lebourg Oct. 20, 

1. IN A DEVICE FOR DETONATING AN EXPLOSIVE CHARGE IN A TUBULAR STRUCTURE, THE COMBINATION OF; AN ELONGATED MEMBER HAVING ONE END ADAPTED FOR CONNECTION TO A LINE FOR SUSPENDING SAID MEMBER IN A TUBULAR STRUCTURE; MEANS AT THE OTHER END OF SAID ELONGATED MEMBER FOR SECURING SAID MEMBER AGAINST MOVEMENT RELATIVE TO SAID TUBULAR STRUCTURE WHEN SUSPENDED THEREIN; SUPPORT MEANS CARRIED BY SAID ELONGATED MEMBER; SAID SUPPORT MEANS BEING MOVABLE ON SAID ELONGATED MEMBER; MEANS COUPLED TO SAID SUPPORT MEANS FOR SECURING SAID SUPPORT MEANS AGAINST MOVEMENT RELATIVE TO SAID TUBULAR STRUCTURE WHEN SUSPENDED THEREIN; 